Rotation in Two and Three Dimensions

The Physics Hypertextbook™
© 1998-2008 by Glenn Elert -- A Work in Progress
All Rights Reserved -- Fair Use Encouraged

prev | up | next

---

Discussion

Precession and nutation

∑τ =	d L
	dt

Combinations of rotations are not commutative

Summary

• bullet

Problems

practice

1. Write something.
   • Answer it.
2. Write something else.
   • Answer it.
3. Write something different.
   • Answer it.
4. Write something completely different.
   • Answer it.

conceptual

1. This is a real problem that I am sure has something to do with precession. There's really only one interesting question in the physics of football (American football — not soccer) When a quarterback throws a "tight" spiral, he has to do it by putting a large rate of spin on the ball and he has to do it by launching it with no angle of attack; that is, the long axis of the ball has to be parallel to the velocity of the ball. When he does that, the ball will execute a motion in which its long axis maintains its tangency to the direction of motion. How can that be? What's causing its rotation? (I would ask, what's causing its precession?)

numerical

1. more problems

Resources

• general
  • The Mechanical Universe and Beyond (video on demand, login required)
    • Torques and Gyroscopes, From spinning tops to the precession of the equinoxes.
• miscellaneous
  • Mars Pathfinder - Rotational and Orbital Dynamics, Jet Propulsion Laboratory, NASA

---

prev | up | next

Another quality webpage by Glenn Elert

home | contact bent | chaos | eworld | facts | physics